In lubes solvent extraction and dewaxing refining processes, rapid identification of the ability for a crude oil, crude fraction, or other potential lube feedstock for making a desirable lubricating oil is important for screening and economic evaluation of potential feedstocks. Early determination of the ability for a (crude) feedstock to make a desirable lubricating oil can allow previously undemonstrated crudes to be quickly processed into lubes, leading to more lubes feedstock flexibility and better refinery profitability. In this process, quick differentiation of “challenged” crudes from normal lubes is valuable, since “challenged” lube crudes should not be processed into lubes at a high percentage within a feed slate for quality and/or economic reasons. Otherwise, off-spec de-waxed oils (DWO) from “challenged” crudes might be generated during refinery processing, which could result in downgrade of valuable DWO into an FCC feedstock.